It is well known that porous floors, particularly concrete floors, corrode or otherwise deteriorate in the presence of numerous materials such as inorganic acids, organic solvents, and solutions of salts. In the latter case, deterioration of the concrete is thought to occur by diffusion of the salt into the porous concrete where it crystallizes causing expansion and cracking.
In order to protect the floor surfaces from such corrosion or deterioration various coverings have been employed including coatings of naturally derived materials such as asphalts and linseed oil and of synthetic polymeric materials, particularly epoxies. Merely by way of examples, U.S. Pat. Nos. 4,078,117; 3,861,944; 4,057,664; 4,091,148; 3,850,661; 4,153,743; 3,811,911; and 4,004,054 discloses various materials useful in protecting floor or concrete surfaces from corrosion or deterioration.
None of the floor covering materials so employed is entirely satisfactory. Some materials fail to provide adequate protection or are completely ineffective under certain conditions. Thus, for example, a common problem encountered is due to the different coefficients of expansion of the underlying floor and of the covering material. Upon sudden changes in the temperature of the floor, cracking results requiring floor repair or replacement. In addition to the need to protect the underlying floor substrate from deterioration, it is often desirable to provide certain properties such as improved chemical resistance, abrasion resistance, the capability of bridging shrinkage cracks, control joints and the like, and thermal shock resistance.
To provide such properties, while also providing protection of the underlying floor substrate, multilayered or laminated floor constructions have been utilized. In such a structure, each of the various layers provides some desired property or properties so that the composite floor construction exhibits properties not obtainable with a single coating or covering layer.
Thus, for example, U.S. Pat. No. 3,510,339 discloses a coating system for floors, including concrete floors, which includes an epoxy resin primer coating, an aggregate layer which includes a filler such as quartz deposited thereover and top coating layer of an epoxy resin.
U.S. Pat. Nos. 4,013,598 and 3,908,043 teach a floor construction which includes a concrete substrate, a primer coating layer of an epoxy resin, an intermediate layer of a synthetic resin such as an epoxy resin, and a top coating layer of a polyurethane layer.
U.S. Pat. No. 3,795,533 discloses a method for preserving and/or strengthening porous materials including concrete which involves impregnating the concrete with repeated coatings of an epoxy resin which may additionally include an inert filler, such as silica, and placing a top coating layer of a polyurethane resin thereover.
U.S. Pat. No. 3,993,823 discloses a synthetic resin floor construction which comprises a concrete substrate, a primer coat of epoxy resin, an intermediate layer of an epoxy resin and filler and a top coat of a polyester resin.
Finally, U.S. Pat. No. 4,025,683 discloses a laminated coating construction which includes a concrete substrate, a primer coat of a synthetic resin, an intermediate coating layer of polyurethane resin and filler, a tack coat of asphalt, and a layer of asphaltic concrete placed thereover.
The discovery of improved hardening agents for use in coatings greatly expanded the potential of laminated floor constructions based upon the use of synthetic resins. The incorporation of such hardening agents in floor constructions may provide permanent structural flexibility so that thermal shock or cycling would cause little or no damage to the floor. Also, the utilization of such agents enabled curing of the synthetic resins to be accomplished at low temperatures and in the presence of water.
Several years ago a multi-layered floor construction was developed which provided certain of the desirable properties discussed hereinabove. This multi-layered floor construction included a floor substrate, particularly a concrete substrate, a primer coating layer of an epoxy resin, a fiberglass-reinforced base coating layer of an epoxy resin, a self-leveling top coating layer of an epoxy resin having filler material incorporated therein, and a grit coat of an epoxy resin having a particle filler material included therein.
Although this laminated floor construction provided numerous desirable properties, it suffered from several disadvantages. Thus, this floor construction had a tendency to stain under certain circumstances such as upon exposure to certain foods, pharmaceutical materials, and urine which may contact the floor in laboratory animal rooms. Also, prior art floor covering systems based upon epoxy resins tended to yellow or chalk upon exposure to ultraviolet or infrared light. Another disadvantage is that with epoxy sealer or grit coating layers it was not possible to obtain both self-leveling properties and non-glossy surface characteristics. Moreover, the previous laminated floors provided less than optimally desirable abrasion resistance, acid resistance and color stability.
In accordance with the present invention, multi-layered, fiberglass-reinforced floor constructions are disclosed which overcome the aforementioned disadvantages and provide improved chemical resistance, abrasion resistance, thermal shock resistance and color stability. Moreover, the laminated floor constructions of this invention provide high stain resistance and retard or prevent the growth of fungi or bacteria. As a result these floor constructions are highly desirable for use in the food and pharmaceutical industries where substantial governmental regulation exists requiring high standards of cleanliness, non-toxicity and the like.